Manufacture of aliphatic ketones



Patented Mar. 27, 1934 ETED STATES.

PATENT OFFICE No Drawing. Application November 18, 1930,

Serial No. 496,571. 18, 1929 6 Claims.

This invention relates to the production of aliphatic ketones fromaliphatic primary alcohols, and especially to the production of acetonefrom ethyl alcohol.

According to the invention I have found that acetone can readily beprepared by causing ethyl alcohol to react at relatively hightemperatures with barium hydroxide to produce barium acetate, and bythermally decomposing the barium acetate so produced either continuouslywith its production or as a separate heating operation into acetone.

I have further found that homologous alcohols react in a similar mannerto ethyl alcohol, producing the barium salts of the homologous fattyacids which can likewise be thermally decomposed, either continuouslywith their production or as a separate heating operation, to produce thehomologous ketones.

Thus, for instance, diethyl ketone can readily be prepared by causingpropyl alcohol to react with barium hydroxide and by thermallydecomposing the barium propionate so formed continuously with itsproduction or as a separate heating operation.

The alcohol can be caused to react with the barium hydroxide attemperatures from between about 200 and 500 (3., temperatures betweenabout 300 and 500 C. being especially useful in cases where the bariumsalt of the fatty acid is to be decomposed continuously with itsproduction, whilst temperatures of between about 250 and 350 C. areespecially advantageous in cases where it is desired to decompose thebarium salt of the fatty acid in a separate heating operation.

In performing the invention I preferably perform the thermaldecomposition of the barium salt of the fatty acid continuously with itsproduction. Thus, for instance, I may pass ethyl alcohol vapour orvapour of other primary aliphatic alcohols in a continuous stream overbarium hydroxide heated to a temperature between about 300 and 500 C.,and preferably between 400 and 500 C. The ketone so produced may beseparated from the reaction vapours in any convenient way, as forinstance by subjecting the reaction vapours to condensation. If it isdesired or necessary to free the reaction product from unconvertedalcohol the condensed reaction product may be subjected to fractionaldistillation.

In cases where it is desired to perform decomposition of the barium saltof the fatty acid as an operation separate from its production, thealcohol vapour may be passed in contact with In Great Britain December abarium hydroxide in any instance alcohol vapour may over bariumhydroxide at a tween about 250 and 350 C., whereafter the passage of thealcohol vapour may be stopped and the barium salt of the fatty acidproduced may be decomposed into the ketone by heating in the same or ina different reaction vessel, at a temperature between about 400 and 500C.

If desired the process of the invention may be performed by passing thealcohol vapour over barium hydroxide at arather low temperature (e. g.250-350 C.) in order to convert the barium hydroxide partially orentirely into barium acetate (or other fatty acid salt of barium),whereafter the temperature may be raised (e. g. to a temperature betweenabout 350 and 500 C.) to decompose the barium acetate (or other fattyacid salt of barium) into the ketone, and if desired the passage of thealcohol vapour may be continued during the heating to such highertemperature, whereby the alcohol vapour so passed can be convertedcontinuously to the ketone.

The reaction vessel for use in the invention can, of course, be composedof any material capable of resisting corrosion by the barium hydroxideand of resisting the temperatures employed, e. g. copper, stainlesssteels (e. g. staybrite) or fused silica may be mentioned asconstructional materials which are very suitable.

The following example serves to illustrate a convenient form ofexecution of the invention, but it is to be understood that theinvention is in no way limited thereto.

be passed in a stream temperature of be- Example passed in a continuous(e. g. of

ide, and maintained at a temperature of between about 410 and 420 C.

The resulting acetone may, if desired be subjected to fractionaldistillation in order to obtain it in as pure a form as possible.

What I claim and desire to secure by Letters Patent is:--

l. Process for the manufacture of aliphatic ketones, which comprisestreating primary aliphatic alcohols in the vapor phase having at leasttwo carbon atoms with barium hydroxide at temperatures between 250 C.and 350 C. to cause the alcohols to react with barium hydroxide toproduce the barium salt of the acid corresponding to the alcoholemployed, and then convenient way. For

thermally decomposing the barium salt between 400 C. and 500 C. toproduce the ketone.

2. Process for the manufacture of acetone, which comprises treatingethyl alcohol in the vapor phase with barium hydroxide at temperaturesbetween about 250 C. and 350 C. to cause the alcohol to react withbarium hydroxide to produce barium acetate, and thenthermallydecomposing the barium acetate between 400 C. and 500 C. to produceacetone.

3. Process for the manufacture of aliphatic ketones, which comprisestreating primary aliphatic alcohols in the vapor phase having at leasttwo carbon atoms with barium hydroxide at temperatures between about 250C. and 350 C. to cause the alcohols to react with barium hydroxide toproduce the barium salt of the acid corresponding to the alcoholemployed, and thermally decomposing the barium salt between 400 C. and500 C. to produce the ketone continuous ly with the production of thebarium salt.

4. Process for the manufacture of acetone,

which comprises treating ethyl alcohol in the vapor phase with bariumhydroxide at temperatures between about 250 C. and 350 C. to cause thealcohol to react with barium hydroxide to produce barium acetate andthermally decomposing the barium acetate between 400 C. and 500 C. toproduce acetone continuously with the production of the barium acetate.

5. Process for the manufacture of aliphatic ketones, which comprisescausing primary aliphatic alcohols having at least two carbon atoms toreact at temperatures of between about 250 and 350 C. upon bariumhydroxide and thermally decomposing the barium salt so produced attemperatures of between about 400 and 500 C.

6. Process for the manufacture of acetone, which comprises causing ethylalcohol to react at temperatures of between 250 and 350 C. upon bariumhydroxide and thermally decomposing the barium acetate so produced attemperatures of between about 400 to 500 C.

HENRY DREYFUS.

